iwlwifi: mvm: fix out of bounds access to tid_to_mac80211_ac

When tid_tspec was set to IWL_TID_NON_QOS (8) this led to an
out of bounds access to the tid_to_mac80211_ac array whose size
is 7. Fix this.
Signed-off-by: Eyal Shapira <eyalx.shapira@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/tx.c

@@ -108,8 +108,12 @@ void iwl_mvm_set_tx_cmd(struct iwl_mvm *mvm, struct sk_buff *skb,
 			tx_flags &= ~TX_CMD_FLG_SEQ_CTL;
 	}
 
-	/* tid_tspec will default to 0 = BE when QOS isn't enabled */
-	ac = tid_to_mac80211_ac[tx_cmd->tid_tspec];
+	/* Default to 0 (BE) when tid_spec is set to IWL_TID_NON_QOS */
+	if (tx_cmd->tid_tspec < IWL_MAX_TID_COUNT)
+		ac = tid_to_mac80211_ac[tx_cmd->tid_tspec];
+	else
+		ac = tid_to_mac80211_ac[0];
+
 	tx_flags |= iwl_mvm_bt_coex_tx_prio(mvm, hdr, info, ac) <<
 			TX_CMD_FLG_BT_PRIO_POS;